1. Field of the Invention
The present invention relates to welding helmet technology, and more particularly to the retention of removable eye shields or electronic quick change ("CQC") cartridges within a welding helmet.
2. Description of Related Art
Traditionally, welding helmets had darkened lenses which protected the user's eyes from the intense light caused by sparks discharged during welding. The intense light, without such protection, could cause serious injuries to the welder such as retinal burnout. However, because the lenses were unduly dark, the lenses had to be raised away from the user's eyes when the user needed light to see his or her work, and lowered during welding. Consequently, the helmets did not provide sufficient protection to the user because the lenses did not provide continuous eye protection, which was particularly critical in emergency situations.
The manual raising or lowering of the eyepiece was eliminated by the use of the liquid crystal display ("LCD") lens, as characterized by U.S. Pat. No. Re. 29,684 Gordon. The '684 patent teaches a fixed position LCD lens comprising a layer of liquid crystal material enclosed between two opposing parallel plates coated with transparent conducting films. The liquid crystal material is arranged such that when a suitable electrical potential is established across the conducting films and the liquid crystal layer, the lens assembly changes from a uniform light transmitting condition to a uniform eye protecting approximately opaque condition. Thus, as the welder creates a spark, the liquid crystal changes from the light transmitting condition to the eye protecting condition. A shortcoming of the '684 Patent, however, is that the LCD lens cannot be removed from the helmet such as needed when the lens becomes damaged or otherwise.
An EQC cartridge is a device which has an adjustable LCD lens that can be removed from the helmet. In the prior art, the EQC cartridge is electrically coupled to a source in the helmet, whereby the operator can manually adjust the light transmittancy through the lens. The EQC cartridge is held into place on the helmet by a spring cartridge. To install the spring cartridge, the EQC cartridge is placed onto the helmet and the spring cartridge is thereafter placed around the EQC cartridge. However, in addition to requiring an extra part, i.e. the spring cartridge, the installation and removal of the EQC cartridge with the spring cartridge is extremely cumbersome.
A face shield filter plate retainer for welding helmets that does not employ spring cartridges or other additional parts is taught by U.S. Pat. No. 5,062,116 Siegal. The '116 patent discloses a face-protecting device that includes a filter plate retained on a support ledge on the exterior of the helmet by means of a flexible filter plate retainer provided with integral fastening means that protect inwardly therefrom. The retainer, however, mounts the lens to the front of the helmet, which is inadequate for use with an EQC cartridge. An EQC cartridge with its intricate controls is extremely expensive and thus requires protection within the helmet. Furthermore, it is inconvenient for the user to have to remove the helmet and rotate it to adjust the controls.
With the above considerations in mind, an object of the present invention is to provide a system for retaining an EQC cartridge within a welding helmet which eliminates the spring cartridge that currently holds the EQC cartridge in place.
It is a further object of the invention to provide a retention system in which the EQC cartridge is easily installable and removable due to damage or inoperateness.
Finally, it is still another further object of this invention to provide a retention system in which the EQC cartridge is attached to the helmet from the inside to protect the EQC cartridge electronics from external hazards and to facilitate the adjustment of the controls by the user.